High resolution near IR spectrometer for the diffuse interstellar medium
Session 10 -- Remote Observing, Ground-Based Telescopes and Instruments
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

## [10.10] High resolution near IR spectrometer for the diffuse interstellar medium

A.S.Kutyrev (GSFC/NRC), C.L.Bennet, S.H.Moseley (GSFC), F.L.Roesler (UW-Madison)

We have developed a pressure scanning cold Fabry-Perot spectrometer for the study of the warm diffuse component of the interstellar medium. In order to reduce thermal background and increase sensitivity optical components are cooled to 77K in a LN\$_2\$ cryostat. Wavelength scanning is accomplished by changing N\$_2\$ pressure in the etalon chamber. The instrument can be scanned over its free spectral range of 300\$km\;s^{-1}\$, and it has a velocity resolution of 20\$km\;s^{-1}\$. A high performance InSb photodiode is used with an integrating preamplifier.

This instrument, with its high spectral resolution and large field of view (\$\approx\$ 1\$^o\$) is well suited for observation of line emission from extended low surface brightness objects. Its design has been developed to allow detection of the diffuse Brackett-gamma and Brackett-alpha emission lines from the warm ionized component of the ISM.